Method for producing valuable hydrocarbons in the carbonization of bituminous fuels or the like



Patented Mar. 19, 1940 UNITED STATES METHOD FOR PRODUCING VALUABLE HYDROCARBONS IN THE OARBONIZATION or BITUMINOUS FUELS on THE LIKE Heinrich Koppers, Essen, Germany, assignor, by

mesne assignments, to Koppers Company, Pittsburgh, Pa., a corporation of Delaware Application April 7 1937, Serial No. 135,420

In Germany April 9, 1936 2 Claims.

The invention relates to the recovery of valuable hydrocarbons, especially of aromatic hydrocarbons, such as benzol and its homologues by heat treatment of gaseous products, developed when the bituminous fuel is subjected to carbonization at comparatively low temperatures in chamber or retort ovens for the production of gas and coke.

Aromatic hydrocarbons are formed, if the carbonizing temperature is rather high. The hydrocarbons obtained -by the carbonization or distillation of bituminous fuels at low temperatures, especially below a temperature of about 750 C. are mainly of the aliphatic nature, benzolic hydrocarbons being only formed in a rather small small quantity. Since benzol and homologues are considerably more valuable than the aliphatic constituents of a low boiling point, it is also desirable to increase the yield of aromatic hydrocarbons when carbonizing the bituminous fuels at a low or medium temperature.- This may be arrived at by a suitable heat treatment of gases and vapours, generated during the carbonization process. If the distilling products are heated to such a temperature, which preferably lies at about BOO-850 C., aliphatic products are converted into aromatic hydrocarbons.

The present invention consists in carrying out such heat treatment of the distillation products during the carbonization process at a low or medium temperature for the purpose of improving the yield of benzol hydrocarbons, and provides for the introduction of a certain quantity of air or the like into the gas collecting space of the coking oven during the carbonization process. Therein, the as is burnt together with a portion of the combustible products present in the gas collecting space and by varying the quantity of the air supplied, the temperature of the gases in the collecting space may be adjusted in the desiredway.

I have found, that the desired heat treatment of the hydrocarbons can be most effectively carried out in this described way, without causing any difficulties during theoperation and without resulting in an'appreciably lower quality of the distilling gas.

Still further objects of my present invention may be taken from the following description'of a preferred embodiment therefor in connection with the accompanying drawing, which shows a horizontal chamber oven for the production of gas and coke constructed according to my invention.

Figure 1 is a longitudinal section through the oven, on lines I-I of Figure 2 and Figure 2'is a ver'tical section on lines 11-11 of Figure 1.

The oven as illustrated on the drawing is fitted with chambers I, la, into which the fuel to be carbonized is charged. The chambers are formed brick walls 2 provided with ordior other suitable by refractory nary vertical heating flues 3,

means, for heating the brick walls. The regeno erators 3a are situated beneath the chambers I.

- The coal charged into the chambers I, la is heated and consequently coked, whereby the bituminous matters of the coal are driven-01f in the form of gaseous hydrocarbons and tarry ya- 15 pours. When the whole charge is coked, the coke is pushed out through the chamber openings at one end of the chamber, after the doors 6 are removed. Then another coking period is started by filling fresh coal into the chamber in the usual way.

The top of each chamber is covered by the roof 4, in which a series of closable charging openings 5 are arranged. On one side of the chamber, there is arranged an opening I, to 9 which is connectedthe ascension pipe 8, leading to the hydraulic main 9.

Preferably, another opening III is provided in the oven roof at the end of the coking chamber, opposite the ascension pipe. The openings I0 of the adjacent coking chambers I are arranged on the same line, so that they can be interconnected by means of removable U-shaped pipes I I. A shut-off valve I2, to be operated from outside, is inserted into the connecting pipe II.' By means of the valve I2 the connection between the oven chambers coupled to the pipe I I may be interrupted.

Furthermore, a compressed air line I3 is provided on the oven roof. This line is controlled 40 by regulating and shut-off valves- I4 and is in connection with nozzles I5, extending through v the interior of the connecting pipes II.

During the carbonization process, preferably at the beginning of each coking period, a definite adjustable quantity of compressed air is delivered through the pipeline I5 into the opening III of chamber I. Simultaneously, the shut-ofi valve I2 is preferably opened, so that a certain quantity of hot distilling gas will overflow into the chamber I from the chamber Ia. If at this time the carbonization in chamber Ia has not progressed to the stage of coking at which its distillate gas is at a temperature higher than the temperature of the distillate gas escaping from chamber 5, which may have been freshly charged with fuel shortly before, the air is then blown into the roof opening Ill through the nozzle l5, and mixes with the combustible gases, which are present in the opening ill or in the gas collecting space l6 above the charge, where the combustion takes place followed by an increase in temperature of the gases in the collecting space. The combustion products together with the unbumt distillation gases are withdrawn through the opening I, ascension pipe 8 and the hydraulic main 9. Since only a comparatively small quantity of air will have to be added through the nozzles I5 to increase the temperature in the gas collecting space, the dilution of the distilling gas, resulting from the combustion products, is practically nil.

Moreover the temperature in the gas collecting space may further be controlled preferably by the provision of the charging holes 5 with double closures I1, of which the upper ones may be lifted separately if required, so that the cooling effect of the charging holes will be increased.

Under normal operating conditions, an increased gas pressure exists in the gas collecting space l6 of the oven, for which reason the pressure of the make-up air to be added through the nozzles l5 has to be increased accordingly.

By adjusting the quantity of air delivered through the nozzles IS, the temperature may be increased in a practical manner in the gas collecting space in the desired way. Preferably, the quantity of air to be added is such, ,that the gas temperature rises to about '75( l85 0.C. Under certain conditions, it is, moreover, of advantage to increase the-air supply toward the end of the carbonization period or to introduce the air only at the end of the carbonization period. In such cases, only a small portion ofthe coke produced in the chamber will be burnt, by which a preferred increase of the temperature in the walls of the gas collecting space is obtained, which has a favourable influence upon the additional heat treatment for the distillation products to be made in the subsequent operating period, even if no air is to be added to the gas collecting space at the beginning of the next subsequent coking period.

I have now described my present invention on the lines of a preferred embodiment thereof, but my invention is not limited in all its aspects to the mode of carrying out as described and shown, since the invention may be variously embodied within the scope of the following'claims.

I claim:

1. In a process for improving the yield of valuable hydrocarbons, especially aromatic-constituents, in the low temperature gaseous products evolved in retort ovens during low temperature carbonization of a coking charge therein at a temperature below 750 C. by externally applied coking heat to produce gas and coke, which process involves subjecting the evolved gases after they rise to, and while flowing over the coking charge through a gas collecting olfiiow space to an ofitake for withdrawal above the coking charge in the retort chambers, to an increased temperature in the gas collecting of!- flow space for converting aliphatics to aromatics in the gas in advance of out-flow from such space, the improvement comprising effecting the increase in temperature for such purpose by introducing air into the distillate gas in the gas collecting space in amount to raise the temperature of the gas at a maximum to 800-850 C. by combustion of part of the distillation gases after they have risen to the gas space and are flowing over the charge to the outlet therefor.

2. AIprocess as claimed in claim 1, and in which the air is introduced as aforesaid but during theearly stage of coking, and in which the hot distillation gas from an adjacent coking charge in another oven is also introduced, together with the air, into the gas collecting space of the oven in which the air is being introduced.

HEINRICH KOPPERS. 

